Intra- and inter-observer agreements in detecting peri-implant bone defects between periapical radiography and cone beam computed tomography: A clinical study

Background/purpose: Information regarding agreements between periapical radio-graph (PA) and cone beam computed tomography (CBCT) in detecting peri-implant defect is still scarce. The aim of this clinical study was to compare agreements between PA and CBCT in detecting peri-implant bone defect. Materials and methods: This retrospective clinical study enrolled 32 patients with both PA and CBCT filmed right after implant placement. Four modalities were used for film reading: PA1 (orig-inal), PA2 (enhanced brightness/contrast), CBCT1 (selected axial and mesial-distal direction im-ages) and CBCT2 (all data with software). 2 experienced and 2 inexperienced observers scored all films. Intra-and inter-observer agreements were estimated with Cohen's kappa coefficient. Cate-gorized agreements were compared and differences among four modalities were calculated. Results: Agreements of PA were better than CBCT when detecting peri-implant bone defects in inter-observer agreements (median kappa 0.471 vs. 0.192; p = 0.016). Moreover, agreements in experienced observers were better than inexperienced observers (median kappa 0.883 vs. 0.567; p < 0.001). There was significant difference among four modalities except for experienced observer 2 (p = 0.218). Conclusion: Agreements of PA are better than CBCT when detecting peri-implant bone defects, especially for inter-observer agreements. Experienced observers are more consistent in assess-ment than inexperienced ones. & ordf; 2020 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons. org/licenses/by-nc-nd/4.0/).